Program won't run?

I installed the program Friday and it worked OK all day. Saturday the program would not start or run, I removed and replaced it and restarted my computer and the program worked great. Sunday morning the browser would not start again, I removed and replaced the program and it ran all day Sunday. Monday morning I start my computer and try to start Vivaldi and it won't start again.
HP computer, laptop, Windows 10. I don't have any problems running Firefox or IE. Vivaldi just won't run. Any ideas as to why and how to fix it?

@keithmj
Does it appear in the taskmanager anyway?
And does it start when you hit the vivaldi Logo a second time?
I am asking because there is an issue where vivaldi starts the first window "outside" of your screen and only when you start a second window it appears on your monitor.

@zaibon
It shows in the Taskmanager under startup only and I can click on the icon twice and the program won't run. As long as I don't turn my computer off at night I don't have any problems. I have to remove and replace the program to get it to run.

Now I can't get the program to run even after removing and replacing the program and a restart of the computer. As soon as I uninstall the program the browser will open that wants a reason for the uninstall. But it won't open other times?

@keithmj Among other things, you may now have some corrupted files in your user profile folders (aka Default folder). These customization and data sub-folders/files are intentionally left behind during an uninstall operation so as to be available upon a reinstall. However, they can preserve and carry some problems into a fresh reinstall. With no Vivaldi running, try tracking down and renaming the Default folder to something else; then try either restarting or uninstalling Vivaldi. Vivaldi will automatically create a new, fresh Default folder that will hopefully at least get it back into operation.

The renaming of the old Default folder preserves any specific customization files that a user might later wish to try transferring over into the new Default folder (though there's then the risk of re-importing the original problems if they involve the transferred files).

In a Win10 multi-user installation of Vivaldi, the Default folder is located at:
C:\Users*Your Username*\AppData\Local\Vivaldi\User Data\Default

@Blackbird
I went in and deleted the program and then deleted the folder that the Default is in and reinstalled the program. The program started right up so I went in to do some browsing, I was in the program about two minutes and it closed on its' own. I tried to start the program and it won't start again. I'll keep playing the next few days and then I am hanging it up.

@luetage
Yeah right, do you realize how much work that would be? It would be easier to buy a new computer. I'll just delete the program and stay with what I am using now. But thanks for the reply, just not practical at this point.

@keithmj
Just a shot into the blue: What happens when you install vivaldi as a standalone version?
To do so click in the install window on Advanced --> open the dropdown menu Install Type --> select Install as Standalone--> choose a folder as you like.

Well I got the program to start and stay running. Here is what I did. I removed Chrome and a few other programs, removed Vivaldi and all the folders for it. Restarted the computer and reinstalled Vivaldi, restarted the computer and the program started and has been working since. I will know tomorrow when I restart the computer.
Thanks to those who gave an answer for the problem. I never would of thought of removing Chrome. I'll let you know later if that did work.

@keithmj Once upon a time in a couple of forums, I came across some problems with both the early 'new' Opera and early Vivaldi browsers that seemed to involve Windows registry confusion/corruption issues when either browser was installed on a system that also had Chrome or other chromium-related browsers as their foundation. The reported occurrences regarding both browsers seemed to have faded away as time and version improvements passed, and this is the first one I've seen in over a year that could possibly involve the same kind of thing. In any case, that's why I asked if you had other chromium browsers on the same system. Please do let us know how this turns out after you restart your system.

@Blackbird
Well, I started my computer and let it run for about 45 minutes and clicked on the Vivaldi icon and waited and waited and the program never opened. It does not show up in Task Manager. The program will not open again. Removing the programs didn't help. Back to the drawing board, I'll keep trucking.
I deleted the program again, deleted all the folders and reinstalled the program as a Stand Alone program and I will find out tomorrow when I restart the computer if it works.
I made a desktop Icon for the program and noticed that two other program icons had changed to the red square with the white V in it? Why would my other icons change? But the programs still open as they should. I hope this might help to find the problem.

@keithmj
To try to recap events to date, per my understanding of what has been posted:
-- you have (usually) been able to install Vivaldi and it auto-appears on the screen at the end of the installation process.
-- a Vivaldi icon appears in the Startup folder at the time of installation.
-- after the computer is turned off, Vivaldi refuses to restart, either from the icon in the Startup folder or from Start-menu or desktop icons. In these cases, a Vivaldi process is not still running in Task Manager.

Perhaps I'm missing it, but along the way did you try to just manually close Vivaldi while it's running after being installed, wait a minute, and restart it from an icon? If so, did it then restart? From what I'm interpreting from your description thus far, it seems like Vivaldi is only performing its initial post-installation auto-start for you. That is, it seems like the only time you could get Vivaldi to run was by reinstalling to cause the installer post-installation auto-start to occur. If so, it appears that the program is either not able to properly/fully install into the account in use or else for some reason cannot obtain subsequent access to its necessary startup files following the installation process.

Installing as a Stand-alone installation would certainly make some changes to the installation scenario and file/folder locations, so it might indeed provide an avoidance of account access/permission issues and is worth a try.

I am having what seems to be the same issue. I posted separately. I observed it in process explorer. The program starts and then shuts down on its own. It never appears on screen, but there is a spike in CPU usage when it starts up. I somehow got it running, I think by double clicking on it in process explorer before it shut down (but I can't be certain).

@oscarrob What are your OS and Vivaldi version numbers, and did you install Vivaldi as a Stand-alone, all-user, or multi-account user? Did it successfully auto-start itself at the end of installing? Is the user account you're using an admin acct? Do you have another Chrome/chromium-based browser installed on the system?

@oscarrob
FWIW, that is exactly the path I followed (Vivaldi stable upgraded via admin from 1.10 to 1.11 for all users) on a Win10 system and have had no startup or other kind of problems. In my case, I use 64-bit Vivaldi. Possible differences: I do not have another chromium-based browser installed on the system (thus far), and I'm currently using only Windows Defender as AV.

@keithmg, the OP, first posted on ~7 August, so if your problems stem from a similar cause, it's unlikely the change to the new Chromium engine (60.0.3112.91) in the 1.11 version was responsible.